混合溶劑法製備金屬鹵化物鈣鈦礦薄膜及其物性探討

鈣鈦礦太陽能電池效率與鈣鈦礦材料結構的均勻性、緻密性、覆蓋性以及厚度有關。原因是有序列且規則的晶格排列有利於載流電子長距離的傳輸並且不易被重組。在本研究當中，我們選用溴摻雜鈣鈦礦材料當作吸光層，並將傳統單一溶劑液相製程法做進一步改善，發展出混合溶劑法製備二維結構的鈣鈦礦薄膜。由於溶於DMF中的鈣鈦礦溶液在介孔層上成膜的均勻性與對介孔層的填充性較差，因而不利於載流電子在內部長距離的傳輸。因此我們加入了極性較小的ODCB來改變其成膜的性質。藉由DMF/ODCB雙溶劑液相製程將PbBr2與C4H9NH3Br以特定比例溶於混合溶劑中，經由塗佈將鈣鈦礦前驅物沉積至玻璃基材上，再利用退火處理得到鈣鈦礦薄膜。此製程所製備出來的薄膜材料可以增加其吸光能力，也可以有效提升太陽能電池元件的轉換效率。我們將製成出的鈣鈦礦薄膜進行光電性質及元件表現分析的測試。主要的分析工作包含(1)以光學顯微鏡(Optical microscopy, OM)、掃描式電子顯微鏡(Scanning electron microscopy, SEM)分析表面形貌；(2)以紫外光/可見光吸收光譜儀(UV-Visible spectrophotometer, UV-Vis)、光致發光光譜儀(Photoluminescence spectrometer, PL)和時間解析光激發螢光光譜儀(Time-Resolved Photo Luminescence spectroscopy, TR-PL)分析基礎光電性質；(3)以拉曼光譜儀、X光繞射分析儀 (X-ray diffraction meter, XRD)分析物性及材料晶體結構。結果證實混合溶劑製程所製備出的鈣鈦礦薄膜結晶性佳、缺陷少和載流電子壽命較長。本實驗現階段已探討出簡易且具有穩定再現性方法以製備二維金屬鹵化物鈣鈦礦薄膜。並且藉此希望能有利於往後超薄二維鈣鈦礦薄膜的發展。

關鍵字

二維鈣鈦礦；混合溶劑製成；結晶性

並列摘要

The efficiency of perovskite solar cells is related to the uniformity, compactness, coverage and thickness of the perovskite material structure. Because the sequenced and regular lattice arrangement would be beneficial to the long-distance transmission of charge carriers and not be recombined easily. In this study, we used bromine-doped perovskite material as the light absorbing layer, and further improved the traditional single solvent liquid phase process, and developed a mixed solvent method to prepare two-dimensional structure of perovskite film. Due to the uniformity of film formation on the mesoporous layer and the poor filling of the mesoporous layer in the perovskite solution dissolved in DMF, it is not conducive to the transmission of the charge carriers at the internal distance. Therefore, we added ODCB to change the properties of its film formation. The reactant PbBr2 and C4H9NH3Br are dissolved in a mixed solvent in a specific ratio by the DMF/ODCB two-solvent liquid phase process, a perovskite precursor is deposited on a glass substrate by coating, and an annealed treatment is performed to obtain a perovskite film. The perovskite film prepared by this method can increase the light absorbing ability and effectively improve the conversion efficiency of the solar cell component. We will produce a perovskite film for testing the photoelectric properties and component performance analysis. The main analytical work includes (1) analysis of surface morphology by optical microscopy (OM) and scanning electron microscopy (SEM); (2) UV-visible spectrophotometer (UV-Vis), photoluminescence spectrometer (PL) and time-resolved photo luminescence spectroscopy (TR-PL) for analysis of basic optoelectronic properties; (3) the physical properties and the crystal structure of the material were analyzed by Raman spectrometer and X-ray diffraction analyzer. The results confirmed that the perovskite film prepared by the mixed solvent process has good crystallinity, less defects and long lifetime of charge carriers. At this stage of our experiment, a simple and stable reproducible process has been explored to prepare a two-dimensional metal halide perovskite film. We hope this method could be helpful to the development of ultra-thin two-dimensional perovskite film in the future.

並列關鍵字

two-dimensional perovskite ； co-solvent method ； crystallinity

參考文獻

(1) Oregan, B.; Grätzel, M. Nature 1991, 353, 737.

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